>>715817225
If you post your art/what you're working on you'll get better advice, else we can only give you generic advice that may or may not be helpful. 'Shading/lighting/coloring' is very broad topic and it's difficult to give guidance if we don't know what you're going for, your current skill level, etc
>a little touch up with some light coming from behind the characters
You will want to look up rim lighting, that should get you some references to work off of. The most important thing to remember is that you follow the form of the object itself, don't just blindly follow your outermost lines (that will make it look flat). Don't have the time right now to make an example myself but I found this on google which mostly illustrates what I'm trying to say